From Filippo's marriage to Beatrice Lascaris di Tenda, Countess of Biandrate and the widow of Facino Cane—the condottiere who had power between the factions of Filippo's elder brother and his mother, and Caterina Visconti, the regent—Filippo Maria received half a million florins;[4] but when Beatrice was interested in the affairs of state, he accused her of adultery and had her beheaded at the castle of Binasco in 1418.

Despite reports of self-hate, he was purportedly a good politician, and by employing condottieri to Carmagnola, Piccinino—where his troops were stationed at the Battle of Anghiari, in 1440— and with Francesco Sforza, he managed to recover the Lombard portion of his father's duchy.

Venice, urged on by Francesco Bussone da Carmagnola, decided to intervene on the side of Florence (1425) and the war spread to Lombardy.

After a long campaign, Venice conquered Brescia, extending its mainland possessions to the western shores of Lake Garda.

Filippo Maria unsuccessfully sought imperial aid but was constrained to accept the peace proposed by Pope Martin V, favouring Venice and Carmagnola.

He was the last of the Visconti family's in direct male line, and was succeeded in the duchy, after the short-lived Ambrosian republic, by Francesco Sforza (1401–1466).

The oldest extant Tarot decks, then called carte da trionfi, were probably commissioned by Filippo Maria Visconti.